Neural factors responsible for reversal of functional and morphological claw asymmetry in snapping shrimp will be sought. Peripheral nerve pathways in the snapping claw can trigger a transformation of the pincer claw to a snapper. These pathways will be identified by surgical transection. Neuron properties associated with the triggering of claw transformation will be determined using histological and pharmacological techniques. The transformation of the function and structure of pincer claw motor neurons and their target muscles will be examined by electrophysiological and anatomical techniques. Pharmacological and surgical interference with muscle transformation will be used to discover the nervous agents that cause transformation to occur.